Axios

Smoke from unprecedented wildfires in Canada triggered poor air quality alerts over swaths of the U.S. again on Wednesday, with multiple cities reporting some of the worst air pollution levels of any major city around the world.

The latest: While continuing to choke the Great Lakes region and the upper Midwest Wednesday, the low-lying smoke also drifted southeast and began affecting Ohio Valley and Mid-Atlantic cities.

Heat-related emergency room visits are spiking in Texas, as forecasters warn the dangerously high temperatures will continue to expand into the Lower Mississippi Valley and Mid-South through Thursday.

State of play: Texas saw an average of 837 heat-related emergency department visits per 100,000 from June 18-24 amid ongoing triple-digit temperatures in the record heat wave that's now in its third week — up from 639 visits per 100,000 ER visits for the same period last year, per the CDC.

First, the record Canadian wildfire season exposed residents of the biggest cities in the Northeast and mid-Atlantic to hazardous air quality. Now low-level smoke is taking aim at the Midwest and Ohio Valley.

Why it matters: Wildfire smoke is a public health hazard that can aggravate chronic conditions and pose risks for even healthy populations.

Hundreds of sea lions and dolphins are washing up dead or sick on California beaches due to a toxic offshore algae blooms, officials warn.

Driving the news: The Marine Mammal Care Center, which serves Los Angeles County, is at full capacity as the nonprofit rescue organization responds to "an unprecedented number of animals" falling ill to a neurotoxin from the bloom, CEO John Warner said at a news conference Tuesday.

A new wave of wildfire smoke from Canada reached the U.S. on Tuesday, triggering air quality alerts for millions of people.

Why it matters: Breathing in the unhealthy levels of smoke and other air pollution can increase a person's risk of developing lung and heart conditions, according to the Environmental Protection Agency (EPA).

Despite global commitments to halt the loss of tropical forests, the world lost 10% more primary rainforest in 2022 than it did the year before.

Why it matters: The world's tropical rainforests are a vast terrestrial carbon sink, but they are in jeopardy from logging, agricultural expansion and the effects of climate change, which is altering precipitation patterns.

AtmosZero, a company emerging from stealth today and partnering with a prominent brewery, aims to electrify the production of steam used in industrial applications.

Why it matters: Climate-friendly steam production lacks the buzz of, say, electric vehicles. But it would cut carbon dioxide from multiple industries that use fossil fuel-powered boilers to supply heat.

The Climate Emergency Fund (CEF), which finances disruptive nonviolent climate activism in the U.S. and abroad, is bringing climate scientist Rose Abramoff onto its board, the group tells Axios.

Why it matters: Abramoff lost her job at Oak Ridge Laboratory early this year, after she took part in a protest against fossil fuel sponsorship of the 2022 American Geophysical Union's fall meeting.